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Topic: DPA Little Bit Three DAC (Read 8354 times) previous topic - next topic
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DPA Little Bit Three DAC

Hello all,

I've been using my MacBook for music playing since starting university last October, via my amp and speakers, and I'm beginning to tire of its poor quality output. I'm amazed that no one has released decent drivers for it (as there is all sorts of clipping and distortion through the output which I'm positive is driver related).

Anyway, it has an optical output, so I had a look on eBay for DACs (Digital to Analogue Converters) to do the hard work. I found what is, currently, a bargin DAC manufactured by DPA called the 'Little Bit Three'. http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...em=170077508516

I did some googling, and have gathered that it was a very capable DAC, especially for its price, when it was released in 1995. Unfortunately, I can't find much information about the device itself or even the company - there seem to be many companies using the DPA acronym, and Google picks up on the 'Data Protection Act' as well!

Does anyone know something about this device? Are there any recommendations? I'd like to get hold of the manual, but without knowing where to go for it, I'm a little stuck there.

I hope someone can help,

smiler

DPA Little Bit Three DAC

Reply #1 –
Quote from: smiler on
Does anyone know something about this device? Are there any recommendations? I'd like to get hold of the manual, but without knowing where to go for it, I'm a little stuck there.


Unfortunately DPA Digital went bust quite some time ago which is why you can't find any information about it. They were only a five person company to begin with and overstretched themselves trying to sell very expensive DACs into a contracting market.

In any case there are other problems with the built in audio on the MacBook which cause issues with pops before and after playback as the audio chip goes in and out of power saving.

I'd recommend you get an external USB audio device. If you want it to be able to pass Dolby Digital or DTS then you need to buy an M-Audio Transit as it is the only one available for Mac OS which can do it. If you just want stereo audio then almost anything will do, for example the Edirol UA-1EX has a decent quality DACs in it.

DPA Little Bit Three DAC

Reply #2 –
Quote from: smiler on
I've been using my MacBook for music playing since starting university last October, via my amp and speakers, and I'm beginning to tire of its poor quality output. I'm amazed that no one has released decent drivers for it (as there is all sorts of clipping and distortion through the output which I'm positive is driver related).
My MacBook doesn't seem to produce the audio problems you report. Are you sure that you're not overdriving the MacBook DAC and the match between your MacBook and the receiving equipment is ok ?
Could you be more specefic about the "clipping and distortion" ? It could be a hardware failure as well.
If you're using bootcamp, do you have the same distortion when using Windows XP ?
It's never a bad idea to use an external DAC, but in youre case it might be worth trying to "fix" the MacBook first.

DPA Little Bit Three DAC

Reply #3 –
Quote from: Kees de Visser on
Quote from: smiler on
I've been using my MacBook for music playing since starting university last October, via my amp and speakers, and I'm beginning to tire of its poor quality output. I'm amazed that no one has released decent drivers for it (as there is all sorts of clipping and distortion through the output which I'm positive is driver related).
My MacBook doesn't seem to produce the audio problems you report. Are you sure that you're not overdriving the MacBook DAC and the match between your MacBook and the receiving equipment is ok ?
Could you be more specefic about the "clipping and distortion" ? It could be a hardware failure as well.
If you're using bootcamp, do you have the same distortion when using Windows XP ?
It's never a bad idea to use an external DAC, but in youre case it might be worth trying to "fix" the MacBook first.

I'm using the MacBook to drive a Denon PMA-250SE integrated stereo amplifier at line level. I don't have the manual with me, so I can't quote the exact impedance and voltage level, though it should be 32 mV (I have no idea about the impedance though). I'm using a Cambridge Audio 3.5mm jack -> stereo RCA cable to connect them.

To describe the problem better:
I cannot increase the system volume of my MacBook beyond 90% without hearing unwanted effects. Below this level, it technically behaves fine - I'm just disappointed with its acoustic prowess compared to my CD player at home (one of the original Arcam Alpha models). Above this level, the effects sound to me like clipping. It's like a very slight crackling, almost popping sound, a little like that of vinyl but far subtler, only heard in very busy or loud passages. However, the output at maximum volume is well below line level (comparing with my tuner, attached to another input on the amplifier).

For a slightly fairer comparison, my 5G iPod is faultless via the same set up. At maximum volume, it's also at line level and sounds fine.

Quote from: chelgrian on
In any case there are other problems with the built in audio on the MacBook which cause issues with pops before and after playback as the audio chip goes in and out of power saving.

I can't say that I've ever noticed this, though I'm nearly always playing music or some other sound is playing.

I have read reports about Apple's drivers being 'quieter' in Mac OS X compared to Windows. I haven't installed Boot Camp or Windows, so I cannot compare this myself. If it is possible to test this with a Linux live CD environment, then I could try that.


Any ideas?

smiler

DPA Little Bit Three DAC

Reply #4 –
Quote from: smiler on
Any ideas?
On another forum someone reported similar problems. After turning off "Sound Enhancer" in the iTunes preferences everything was fine. Is your sound enhancer switched off ?

DPA Little Bit Three DAC

Reply #5 –
Quote from: Kees de Visser on
Quote from: smiler on
Any ideas?
On another forum someone reported similar problems. After turning off "Sound Enhancer" in the iTunes preferences everything was fine. Is your sound enhancer switched off ?

I don't use iTunes

Even when I do, I don't have "Sound Enhancer" switched on.


I booted into a Live CD of Ubuntu yesterday. The sound was a little louder, but had some horrid crackling when about 80%-ish or above. This could be the Ubuntu drivers, or it could be the hardware; I'm not sure anymore. I suppose the only definitive test is to try Windows, as there are official Intel drivers for Windows, but that requires installing it and I don't have the time for this at the moment.

Edit: Just to clarify, my main music player is Cog. I also use QuickTime for videos, occasionally VLC - all sound exhibits these problems.

DPA Little Bit Three DAC

Reply #6 –
Quote from: smiler on
Just to clarify, my main music player is Cog. I also use QuickTime for videos, occasionally VLC - all sound exhibits these problems.


If you were at maximum volume in Cog then you are at a factor of 2 gain. The scale is liner and unity gain is with the slider half way along, there is a dent at the unity position.

In VLC the amount of amplifcation available is ever greater then unit gain position only about third of the way along the slider, fortunately the controller tells you what the current gain is.

As far as I can tell both Quicktime player and iTunes are at unity gain with the slider all the way across, so theoretically with the slider at full and the system volume set to maximum you still shouldn't be able to produce distortion out of the computer itself. However this does rely on the sound chip being designed correctly and I haven't seen any evidence that any of the sound chips Apple have used recently have had this particular problem, although they do have other issues.

If your Mac is still under warranty I'd raise the issue with Apple and get your Mac repaired as if you aren't applying extreme gain by mistake it's likely you have a hardware problem.
 

DPA Little Bit Three DAC

Reply #7 –
Quote from: chelgrian on
If you were at maximum volume in Cog then you are at a factor of 2 gain. The scale is liner and unity gain is with the slider half way along, there is a dent at the unity position.

Ah, I see. Thank you for pointing this out; it's something that I hadn't realised. Does a similar behaviour apply to Totem also (which I used under Ubuntu to test the sound)? Although, under Linux, there was a very digital sounding click - not really an analogue clipping.

Now that I know this, I won't attempt to overdrive the output. However, I'm still disappointed by the sonic capabilities, which isn't at all surprising given that it's an Intel embedded chip.

Returning to the original topic, can anyone recommend the DAC I posted in the first post? I was hoping to obtain a second-hand hi-fi DAC for around £50 (as I'm hardly made of money, being a student).

Also, if I were using the optical output, do I assume correctly that having all sliders at unity (Cog centred, system maximum) would give bit-perfect output?

Quote from: chelgrian on
In any case there are other problems with the built in audio on the MacBook which cause issues with pops before and after playback as the audio chip goes in and out of power saving.

Is this when using the optical output?
Quote from: chelgrian on
I'd recommend you get an external USB audio device. If you want it to be able to pass Dolby Digital or DTS then you need to buy an M-Audio Transit as it is the only one available for Mac OS which can do it. If you just want stereo audio then almost anything will do, for example the Edirol UA-1EX has a decent quality DACs in it.

Dolby Digital and DTS output are useless to me - I'll never have the room for a surround-sound set up so a hardware decoder is pointless for me. I just want high quality stereo music and occasionally DVDs.

Is there much of a second-hand market for good condition USB audio devices? At least I know that with hi-fi components, owners generally take good care of them through their working life.